如何跳出 Javascript 中的函数？

Question

Here is the piece of code, note I have commented of what I would like to achieve in the code

const extraHot = () => {
   if (hot === "h") {
      return `extra hot`
   }
// otherwise, do nothing, don't return anything
// (not even an empty string or undefined object)
// I want to break here
}

if (givenAmount >= dict){
// I would like to return "Drink maker makes 1 extra hot sugar and 1 stick"
    return `Drink maker makes 1 ${extraHot()} sugar and 1 stick`
}

The following code will return "undefined" between "makes" and "sugar"

const extraHot = () => {
   if (hot === "h") {
      return `extra hot`
   }
   return
}

The following code will return a space between "makes" and "sugar"

const extraHot = () => {
   if (hot === "h") {
      return `extra hot`
   }
   return ""
}

Answer 1

Your problem is not what the function returns if hot !== "h" , but how you write your template string. In case of if evaluates to true, return ' extra hot ' , and write the template string like

Drink maker makes 1${extraHot()}sugar and 1 stick

Answer 2

The reason you get the space between makes and sugar is because you have one space after makes and another one in front of sugar . To prevent this you would have to change the extra hot function to:

const extraHot = () => {
   if (hot === "h") {
      return "extra hot " # Note the space after hot
   }
   return ""
}

And use it later with:

if (givenAmount >= dict){
    return `Drink maker makes 1 ${extraHot()}sugar and 1 stick`
}

Answer 3

You could normalize functions for returning a string to return an empty string and if some result take an extra space in front of the string or at the end and keep this style.

This approach allowes to chain conditions and get no extra space, if the condition is wrong.

In this case take

const extraHot = () => hot === "h" ? ' extra hot' : '';

and

if (givenAmount >= dict) return `Drink maker makes 1${extraHot()} sugar and 1 stick`;

The result is either

Drink maker makes 1 sugar and 1 stick

or

Drink maker makes 1 extra hot sugar and 1 stick
                   ^^^^^^^^^^